Bevel cutting tip



March 26, 1946. L ARTUNG 2,397,349

BEVEL CUTTING TIP Filed Jan. 8, 1945 Patented Mar. 26, 1946 BEVEL CUTTING TIP Floyd 1. Hartung, Portsmouth, Va., assignor to The Bastian-Blessing Company, Chicago, Ill.,

a corporation of Illinois Application January 8, 1945, Serial No 571,902

Claims.

{The present invention relates to blowpipes and more particularly to blowpipes and processes in which a mixture of oxygen and a liquefied petroleum gas such as propane or butane is employed for the preheat flames in cutting and, washing ferrous metals.

Although the present invention is of particular interest for bevel cutting and washing steel plates, as where the cutting stream of oxygen is directed at an acute angle to the face of the plate, it also constitutes a marked improvement in cutting practices over those conventionally used where the metal is to be lanced or cut at right angles to the face of the plate. Consequently, wherever in the description and claims the Word burning is used in describing the process of the invention and the operation of the tip, cutting, washing and lancing will be contemplated.

Burning a ferrous metal involves the rapid chemical reaction between heated iron and oxygen in which iron heated to its ignition temperature and exposed to high purity oxygen will oxidize with an intense reaction to liberate heat and form oxides which are discharged as slag. As a general rule, the heating of the metal to its ignition point is accomplished by a so-called preheat flame which serves as a pilot for the ignition of metal on its surface when a stream of oxygen is turned on to impinge the heated area. of the metal. Thereafter the intense heat liberated helps to pilot the ignition of the deeper portions of the metal to the extent that oxygen is available and according to the character of the oxygen stream. The oxides formed are molten and flow or are blown away exposing more metal to the action of the oxygen. If the burning action is started at the edge of the metal piece the successive oxidation and removal of oxides will take the form of a groove down the side of the piece.

.The heat resulting from the reaction, however, is not enough to keep thereaction going because of the chilling effect of the surrounding metal and the stream of cutting oxygen in conventional practices. Therefore, it is necessary in most cases to supply further-heat to the point of burning to heat progressively to the ignition point the leading edge of the cut as the stream of cutting oxygen is advanced along a predetermined path. Ehereby the initial groove is deepened into a erf.

By changing the pressure of the oxygen stream, its flow characteristics, the direction of impingement with respect to the metal surface and the speed with which the stream of cutting oxygen is advanced, the burning action generally can be made to produce different types of cuts.

Conventional tips using propane and oxygen as a preheat fuel have the preheat ports ar- .ranged in a predeterminedpattern around the is discharged. The preheat streams are directed to flow along lines approximately parallel with the cutting stream within a shielding wall ex-. tending appreciably beyond the ports. Various shapes of preheat ports are provided, some being deeper in a radial direction than they are wide peripherally while others have variousgeome'tri; cal cross-sectional contours. In all of these tips the inner edge of all preheat ports are spaced from the cutting port by metal stock required ior structural reasons and the flames are. directed to one side of the point of impingement of the Cut-1 ting stream upon the work. This increases the Working area of the preheat flames and since the metal has to approach white heat for ignition,

much heat is wasted before the point of impingement by the cutting stream becomes ignition hot.

In the present invention the preheatflames are directed inwardly in a concentrated cone to convey their heat directly to the point of impingement by the cutting stream. In doing this, all of the flames supply heat to a limitedarea. and provide a faster starting preheat and a faster working preheat as compared with conventional tips where some of the flames miss the edge of the metal at the start and engage the metal only along a path paralleling the projected kerf.

A further difficulty is experienced withv conventional tips in that the preheat flames spread laterally and away from the point of cutting impingement when they strike the metal. This condition is particularly augmented in bevel cutting. In the present invention this difficulty is overcome by directing the flames to mutually converge at an acute angle with respect to each other in a manner counteracting their tendency to spread until after their effective heat has been delivered to the metal where the burning is to take place.

A further difficulty is encountered with conventional tips in that the slag or oxides are caught in an envelope of flaming gases which hinders escape of the oxides except through the keri, whereas, in the present invention one ofthe objects is to direct the flaming gases to a point of convergence to prevent oxide and slag from bouncing and clinging to the tip and to blast the slag laterally from thepoint of convergence. In this way the tip is kept cleaner, runs cooler, and is provided with a longer life. v I

Another object of the invention resides in'preheating an area limited to only that necessary to make the cut, thereby saving fuel and cutting oxygen and providing a narrow and clean kerf.

The invention is further characterized by a convergence pattern of the preheat flames in which the cutting tip can be brought closer to the work than possible conventionally whereby the stream of cutting oxygen can impinge and oxidize the metal to start the kerf before the'stream has a chance to expand after leaving the cutting port.

V as the edge thereof. v I Another object of the invention is to provide beveljcutting. e Fig. 2 is a section taken longitudinally through the tip embodying the preferred form of the in- .reference towhich is hereby. made.

A further object of the invention is to provide a tip which runs so cool that slag will not adhere to it and which so concentrates the fiamesthat the cutting stream must pass through a .Wall-of flame on its way to oxidize the metal; Furthermore, the flame is carried by the cutting oxy- I gen into the'cut to maintain a .properpiloting action along the leading side of the kerf as wellan improved process forheating the: cutting oxygen and for cutting non-magnetic steel by preheating the stream of oxygen before it contacts the. surface of the metal; v d 7 These being among the objects of the invention other and further objects will appear from the drawing, the description relating thereto and the appended claims.

' Inthe drawing: v

Fig. 1' is a side elevation blowpipe illustrating the of a machine carried vention. I v

Fig. 3iis afsection taken upon the line 33 in Fig. 2. v

'Fig. 4 is a section taken upon the line 5- in Fig. g a r a 'Figl 5-is an enlarged section of the end of the tip shown in Fig. 2, and

Fig. 6 is an enlarged-section embodimentof the invention. a

Referring now tothe drawing in further detail a work piece I!) is shown upon a tableror platform H with a remo'vable track l2 resting thereon. 'Afcarriage I3 is mounted upon the track to move along on the track at a predetermined speed as supported by wheels l4. The carriage sup ports anarm l5 adjustable as to height by a handwheel l6 and the arm carries a torch body-I1 ad justable both as to position and angle. 7 Oxygen for the preheat flames and for-cutting is supplied to the torch bodyifrom a high pressure cylinder 18 through acylinder valve 26, a twostage pressure reducing regulator 2!, a hose 22 and a needle valve 23 for the fuel mixture and a cutoff valve' 24 for the cutting stream. Propane for the preheat flames is supplied tothe torch body from a cylinder 25 through a cylinder valve 26, atwo-stage pressure regulator 21, hose '28 and the needle valve 30. I

At its free end, the torch body is provided with a head 3| threaded to receive the tip nut 32 which holds the tip 33 rigidlyin place in a conical cavity showing another (not shown) upon the head 3| as more particu-' larly described in the Wigton Patent 2335330. The cavity is provided with suitable grooves separated by sealing lands (not shown); by which gases are conveyed to the tip 33 without mixing, the cutting oxygen entering at the apex of the cavity.

The tip 33 comprises a base 34 which mates ith the cavity in the head as provided with .2 use of. the invention for to provide a shoulder 42. The enlarged portion 4! is internally threaded to receive a tip core 43 with the innerend of the core sealingagainst theshoulder 42 and with intermediate mating cylindrical surfaces provided for. mutual alignment as indicated at 44.

i Although the tip shown is a so-called tip mixl'ing' tip; i. e. the fuel and oxygen are mixed in .the tip, other tip forms may be used with the .invention'as ,where the preheat fuel and oxygen 1 'ar :mixed'before reaching the tip. To accomplish mixing in the tip there are several passages Y 45 provided through the base from the groove to' conduct preheat oxygen to the tip core as mixed with propane which issupplied through oblique passages 45 leading from the groove 36. Thus confluence of the propane and oxygen is had in the passages 45 as controlled by the needlelv'alves'j 23S and 40. From the head the confluent gases are conducted to the downstream face 41 of the head 34. 7 a

The tip core 43'is formed generallyof a' body portion provided with a central passage 48in communication with the passage 40 for the oxygen "cutting stream. The outside of the core is tapered or inclined as at 50 anda pluralityof preferably symmetrically arranged slots or grooves 5! are cut longitudinallyin the exterior of the core. 'As seen in Fig. 4 these slots are preferably arranged around the passage 48 with their radial radially flanged at its base as at- 53 170 provide an end wall 54 which rests in sealed relationship against a land 55 provided upon the face 41 of the core. The forward side of the flange 53 provides a shoulder 56 against which the nut 32m engages to hold thecore, base and sleeve in assembled relation and snugly in place upon the head3l.

h The sleeve is spaced from the coreover a portionfof its length beginning at thebase 34 to pro-.

vide an'lannular passage 51 for theflow of the fuel-oxygen preheat mixture to the slots 5|. The face 541s roundedas at 58 into the passage 51 to provide a'free flowing contour'for 'thefueloxygen mixture from the chamber 60 provided by the walls 41 and 54 and sealed by the land 55 where the fuel oxygen is subjected to .a further mixing action.v I t The sleeve 52 is tapered as at 6| to follow the contour of the taper 50 on the core at its front end whereby gases flowing through the annular passage 51 are confined to the slots 5| as they leave the passage 51 to beconductecl to the end of the core.

At its outer end, the sleeve 52 extends as at wardly to provide a radial flange 66 which ob- Y structs or lies within a projection'of the ports of the passages 5|"with respect to the direct discharge of gases from the passages 5| and re-I directs their flow convergently inwardly where their maximum effective heat of combustion is concentrated in the path of the cutting oxygen a little infront of the flange 66 where the confluent flames preheat the metalgto its ignition point over an area slightly larger than the impingementiarea of the stream of cutting oxygen.

The control of this convergence and confluence of flames is established effectively when the flange 66 extends inwardly far enough to obstruct substantially a major portion of the port area of the slots maximum convergence very close to the end of the sleeve being obtained when the ports are almost completely covered. 7

Whether the flange be rectangular in its sectional characteristics as shown in Fig. 5 or triangular as shown at 65a, in Fig. 6 is of slight consequence from the functional viewpoint, the rectangular construction shown in Fig. 5- being preferred because slight burning away of the end of the sleeve which occurs under certain conditions does not change the confluence characteristics of the flames whereas a burning away of the end shown in Fig. 6 would to some extent.

In operation, it is desirable to have the flange 66 cover the outer 75 per cent of the port area. This enables the handling of the torch as operators are accustomed to using a torch with the freedom that they can get closer to the work if they desire, a thing they will do automatically as a natural thing when they become familiar with the tip constructed as described.

When the tip is brought to within to a of an inch of the work, the flames will be concentrated over the impingement area of the cutting stream of oxygen. Once the metal is brought to its melting point the putting stream is turned on and the cut begins. The oxygen stream passes through the flame confluence and impinges upon the work. Thereafter the carriage I3 is started and as the tip is moved along the projected kerf,

the oxygen passing through the concentration of flame spreads the flame effect slightly around it to heat the metal along and in the projected kerf. Thus, once the cut is started, the flame is spread automatically to take in a wider area sufficiently to provide a fast cutting preheat.

Furthermore, with the cutting oxygen passing through the flame wall, the outer edges are heated and the flame is carried down into the kerf to eliminate much of the cooling effect which is a burden upon cutting operations, particularly fast cutting.

Whenever the tip is set at an angle to the work for bevel cutting, the flame confluence still engages the point Of cutting impingement and the angle of the bevel is limited only by the edge of the tip dragging on the work.

When cutting non-magnetic steel, it has been found that the preheating of the stream of cutting oxygen is an advantage to provide clean cuts. This heating is augmented by lifting the tip as much as one inch away from the work in some instances to provide a longer period of contact between the confluent flames and the oxygen. This eliminates undue breakdown of the kerf edges and with thin pieces provides a uniform out free from burns and slag.

Throughout the operation of the tip described, any puddling or movement of slag or oxides is subjected to a focal draft induced by the converging flames and burnt gases. This focus is generally between the end of the tip and the work. Therefore, the slag is blown laterally away plished and how various and further modifications and changes can be made without departing from the spirit of the invention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In a blowpipe tip, means defining a plurality of gas passages through which streams of a combustible fuel and oxygen mixture are conducted and terminating in ports throughwhich the streams are discharged in approximately parallel relationship and means including a wall extending beyond the ports parallel with the respective combustible fuel passages and terminating in a flange. lying partly within a projection of the ports with respect to the path of said streams.

2. In a blowpipe tip, means defining a plurality of gas passages through which streams of a combustible fuel and oxygen mixture are conducted and terminating in ports through which the streams are discharged in approximately parallel relationship, and means including a wall extending beyond the ports parallel with the respective combustible fuel passages and terminating in a flange defining a frusto-conical wall lying partly within a projection of the ports with respect to the path of said streams.

3. In a blowpipe tip, means defining a plurality of gas passages through which streams of a mixture of liquefied petroleum gas fuel and oxygen are conducted and terminating in ports through which the streams are discharged in approximately parallel relationship, and means including a wall extending beyond the ports parallel with the respective combustible fuel passages and terminating in a means for directing the radially outer portions of the streams convergingly inwardly at an acute angle after. the streams leave the ports including a flange lying partly within a projection of the ports with respect to the path of said streams and defining an approximately cylindrical opening through which the streams pass.

4. In a tip construction for blowpipes the combination of a central portion having a passage therein for discharging a stream of cutting oxygen along a predetermined path, a sleeve cooperating with the core to form conduits to discharge streams ofpreheat mixture around the passage, said sleeve defining a wall extending beyond the ports parallel With the respective combustible fuel passages, said sleeve including means beyond the wall disposed within a projection of the ports with respect to the path of the streams to direct the streams of preheat mixture sharply inwardly to converge in the path of said stream of cutting oxygen at the point where the oxygen stream is expected to impinge upon a work piece to be cut.

5. In a tip construction for blowpipes, the combination of a central portion having a passage therein for discharging a stream of cutting O ygen along a predetermined path, a sleeve cooperating with the core to form conduits to discharge streams of preheat mixture through ports arranged around the passage, and an inwardly extending flange upon the sleeve spaced from said ports to provide an ignition area and lying partly within a projection of the ports with respect to the path of said streams to direct the outer portions of the streams sharply inwardly to converge in the path of said stream of cutting oxygen.

FLOYD I. HAR'I'UNG. 

